The bodies of four opposition activists have been found near the Zimbabwe capital, after being abducted, the Movement for Democratic Change says. An MDC spokesman accused supporters of President Robert Mugabe of being behind the deaths, ahead of next week's poll. The body of Harare's recently elected opposition mayor's wife has also reportedly been found, badly burnt. International leaders have condemned the violence but Mr Mugabe's allies have denied any responsibility. The MDC says at least 70 of its supporters have now been killed and 25,000 forced from their homes in a state-sponsored campaign of violence ahead of the 27 June presidential run-off. Earlier, Zimbabwe's public broadcaster ZBC said it would no longer carry campaign adverts from the MDC - a decision the opposition said it would challenge. Justice Minister Patrick Chinamasa defended the move, saying international coverage favoured the MDC and never reported the ruling Zanu-PF's position. Correspondents say the ban on adverts will not make a great deal of difference, as news bulletins at the state-run ZBC have always favoured Mr Mugabe, only mentioning the opposition in negative terms. There are no privately controlled radio or TV stations in Zimbabwe and only a few weekly newspapers, which most people cannot afford. Leg irons MDC Secretary General Tendai Biti is expected in court shortly to face treason charges. He was arrested last week after returning from South Africa. The MDC says his arrest is political and is seeking his release on bail. His court appearance on Wednesday, when he was wearing leg irons, was cut short because of a power cut in the magistrates' court. On Thursday, US Secretary of State Condaleeza Rice is to chair an informal UN Security Council meeting on Zimbabwe, in an attempt to maintain international political pressure. "I think that it is time for the leaders of Africa to say to President Mugabe that the people of Zimbabwe deserve a free and fair election," Ms Rice told reporters in Washington. "You cannot intimidate opponents, you cannot put opponents in jail, you cannot threaten them with charges of treason, and be respected in the international community." UN Secretary General Ban Ki-moon on Wednesday expressed concern over the level of violence. But South Africa, Zimbabwe's neighbour, has been leading diplomatic attempts to resolve the situation and is opposed to the council having too much involvement. Peacekeepers South African President Thabo Mbeki met both Mr Mugabe and MDC leader Morgan Tsvangirai separately on Wednesday. South Africa says it is not for the council to resolve disputed elections. Many African leaders still see Mr Mugabe as a hero of the fight against colonialism and have been reluctant to criticise him in public. Mr Mugabe says he is still fighting Western imperialism but some African leaders have started to break ranks. "For me the question that it raises is why do you even call for elections?" Rwanda's President Paul Kagame told reporters in the Rwandan capital, Kigali, Reuters news agency reports. While Kenyan Prime Minister Raila Odinga called for the international community to act in the way it did in Bosnia in the 1990s. "I do not think that we are going to get free and fair elections in Zimbabwe," he said. "What you need in Zimbabwe is an international peacekeeping force so that eventually proper elections can be held," he said. Source: BBC